| Objective: Traumatic optic neuropathy can cause a decline or loss of vision. The treatment of optic nerve injury has been valued by the people, past that the optic nerve injury was a non-renewable, and in recent years, domestic and foreign scholars have found that the optic nerve can be regenerated under certain conditions. Up to now,drug, gene and surgical therapy have been mainly methods to promote the optic nerve regeneration.Early drug treatment is still the main treatment of optic nerve injury. Taurine has a wide physiological and pharmacological effects.It can regulate the body's glucose metabolism and lipid metabolism, and has the role of cell protection, anti-oxidation, improving the visual signal transduction.In this study,we prepared the rats'incomplete optic nerve injury model, using taurine by intraperitoneal injection, to observe the changes of morphology and Nogo-A mRNA expression in the optic nerve. So that to make experiment evidence for the treatment of Taurine to the optic nerve injury.Methods: 84 Female SD rats of clean grade (Hebei Medical University Experimental Animal Center) , weighing 250g±10g, were randomly divided into four groups: normal group with 12 rats, control group with 24 rats, treatment group wirh 24 rats and pretreatment group with 24 rats. The right eyes of rats in control group, treatment group and pretreatment group were produced to the model of optic nerve injury,and the left eyes were not delt with. At 1 hour after injury, the rats of control group were began to give 250mg/kg distilled water by intraperitoneal injection one time per day until the end of the experiment; the rats of treatment group were given 5% Taurine 250mg/kg by intraperitoneal injection (distilled water configuration) one time per day until the end of the experiment; before three days of the injury the rats of pretreatment group were given the same dose of intraperitoneal injection of taurine one time per day until the end of the experiment; the rats of normal group were not dealt with. At the day3, 7, 14, 28, the optic nerve tissue was used for the experimental study.The morphology change of the optic nerve was observed using the optical microscope and the transmission electron microscopy.The expression of Nogo-A mRNA was detected by RT-PCR (reverse transcription polymerase chain reaction, RT-PCR). Used the x±s to express the experimental data, made statistics analysis by analysis of variance, and SPSS 13.0 software package.Results:1.Through HE staining, at day3, 7, 14, 28, the optic nerve structure of normal group was regularity, and the gliocytes line up in order and parallel with the optic nerve fibre. But control group had chaotic optic neuro-mechanism, the nerve fiber was disording, gliocytes had more cell nucleus, some cells had vacuolizations and hypochromatosis. The above-mentioned changes can be observed in the treatment group and the pretreatment group also, but was lighter than the control group.2.The ultrastructure of the optic nerve: The normal optic nerve tissues mainly by the retinal ganglion cells of the axon, myelin sheath, and interstitial glia cells. A large number of axons arranged in neat rows, circularred cross-section of class shape, and surrounded myelin sheath. Compact myelin sheath, showing dense lamellar arrangement of axons, filled with microtubules and microfilaments, the mitochondria and other organelles can be seen. In the control group, the edema of axons, axonal smaller, thinner myelin lysis and lamellar structure splitting can be seen, with the mitochondrial swelling, vacuolization. some microfilaments and microtubules disappeared. The optic nerve of treatment group and pretreatment group can be seen above changes, but the changes of treatment group and pretreatment group was lighter compared with control group.3.The results of axon counting: At day 3, day 7,day 14,day 28 , the number of optic nerve axons of treatment group and pretreatment group were higher than in the control group compared with the same time points, the difference was significant (p<0.05); at day 3, the counts of axon of pretreatment group was higher than the counts of treatment group, the difference was significant (p<0.05); at day 7, day 14 and day 28 , the axon counts of pretreatment group was no significant difference compared the treatment group (p>0.05). In control group, the number of axons was significant difference compared day 3 ,day 7, day 14 with day 28, (p<0.01), the trend was decreasing; In treatment group,the axon counts was significantly different at day 3, day 7, and day 14 (p<0.05), but theret was no significant difference between day 14 and day 28(p>0.05); In pretreatment group,the changing trend of the axon counts was same as in the treatment group.4.The normal optic nerve tissue can be seen Nogo-A mRNA specific amplification bands. In the control group, treatment group and pretreatment group can be seen the Nogo-A mRNA specific amplification bands aslo. In the pretreatment group, treatment group and control group, the ratio of the integral optical density of Nogo-A mRNA andβ-actin was higher than in normal group at day 3,day 7,day 14 and day 28, P<0.05, there was statistically significant.In pretreatment group and treatment group,the ratio of the integral optical density of Nogo-A mRNA andβ-actin was lower than in the control group at day 3, day 7, day 14 and day 28, P<0.05, there was statistically significant.In pretreatment group, the ratio of the integral optical density of Nogo-A mRNA andβ-actin was lower than the treatment group at day 3, P<0.05, there was statistically significant, but at day 7, day 14 and day 28, there was no significant difference, P> 0.05.5. In the control group, the ratio of the integral optical density of Nogo-A mRNA andβ-actin was increasing at day 3, day 7, day 14 and day 28, P <0.05, there was statistically significant. In treatment group, the ratio of integral optical density of Nogo-A mRNA andβ-actin was significantly different between day 3, day 7 and day 14, P<0.05, there was statistically significant, but there was no significantly different between day 14 and day 28, P> 0.05. In pretreatment group, the trend of the ratio was same as in the treatment group. Conclusion:1.The structure and the nerve fibers of the optic nerve after traumatic were disorder.2.Taurine can reduce the general and ultrastructural changes,inhibit the expression of Nogo-A mRNA in the optic nerve tissues after traumatic optic nerve injury;3.Taurine can promote the regeneration and repairment of the optic nerve after injury in a certain degree.
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